1. Field of the Invention
The present invention relates to the field of laboratory centrifuge rotors.
2. Description of Related Art
A standard laboratory centrifuge rotor design offers the advantage of swing-out containers where the direction of force remains constant at all angular speeds. The containers being movable outward, they can be removed from the rotor and be conveniently loaded/unloaded outside the centrifuge. The containers may assume different shapes in order to accept different kinds of sample containers. This feature ranges from large bottles to sample tubules to stacks of microtiter plates received in an open, boxy container.
To generate very high forces shortening centrifuging time, centrifuges of the above species run at very high angular speeds. In the process, the rotor together with the containers is then exposed to very high incident airflows.
In the standard design, the containers preponderantly are designed for being easily suspended between the fork arms, for good loading and also with a plane support surface for safe setup during loading/unloading. As a result the containers can hardly be aerodynamically optimal.
Strong turbulence at the rotor and at the containers arises at high incident airflows. Accordingly high air drag is generated at high angular speeds which in turn entail large rises in air temperature. The high drag must be counteracted by a powerful motor in turn itself dissipating considerable heat. As a result the air temperature rises much in the housing which for safety reasons encloses the entire centrifuge. This temperature rise would degrade the samples to be centrifuges and therefore must be compensated by a cooling unit. These requirements also substantially increase the costs of laboratory centrifuges. Moreover considerable noise is produced by the said air turbulence and can be damped only inadequately by the enclosing housing.
Air chambers such as disclosed in the German patent document 4027993 A1 are known to overcome the above problem. Such an air chamber is an aerodynamically smooth inner housing enclosing the rotor and rotating with it. Within the said air chamber, the air flows jointly with the motor which therefore does not experience turbulence. However such an air chamber incurs the drawback that it encloses the rotor and the containers, as a result of which thermostatting the samples at desired temperatures is much more difficult. The costs of such a design again are very high.
Again the US 2003/0199382 A1 patent document discloses a centrifuge equipped with an air chamber which however is quite shallow and receives the pivotably supported containers only in their swung-out state. The German patent document DE 38 03 255 C1 also shows an air chamber design wherein however the containers are not supported in a manner allowing to remove them and to load them through an aperture in the air chamber cover.
US 2002/0173415 A1 discloses a rotor of the above species of which the rotor arms comprise aerodynamically well shaped external surfaces which are configured peripherally but between which the swung-out containers project widely by their outward zones and thereby induce strong air perturbations.
The German patent document DE 24 47 136 A1 shows an ultracentrifuge, that is a centrifuge of exceedingly high angular speeds, of which the rotor basically moves in a vacuum, thereby eliminating aerodynamics from consideration.
The German patent document DE 101 55 955 C2 shows a rotor of the above species where the aerodynamic problem is resolved in a wholly different manner, namely using turbulence generators mounted on the containers for the purpose of controlling the generated turbulence entrainment.
Lastly, the German patent document DE 25 26 534 A1 shows aerodynamic cladding components for motor trucks.